Pharmacokinetic effects of ginsenoside Rg1 on aconitine, benzoylaconine and aconine by UHPLC-MS/MS

Ginseng and aconite are well-known couplet medicinals. Ginsenoside Rg1 is the main active ingredient in ginseng, and aconitine (AC), benzoylaconine (BAC) and aconine (ACN) are three representative alkaloids in aconite, which belong to the diester alkaloids, monoester alkaloids and alkanolamine alkaloids respectively. The aim of this study was to investigate the pharmacokinetic effects of ginsenoside Rg1 on the three types of alkaloids and to provide evidences for their compatibility mechanism. In this study, the ginsenoside Rg1 was simultaneously intragastrically administered to rats with AC, BAC and ACN, respectively, and the rat plasma was collected at different time points. The plasma drug concentrations of the three types of alkaloids were determined by UHPLC-MS/MS, and the pharmacokinetic parameters were calculated. The results indicated that the peak concentration and area under the concentration-time curve of BAC were significantly increased (P < 0.05), those for AC were decreased (P < 0.05), and the values for ACN did not change after pretreatment with ginsenoside Rg1. It was inferred that ginsenoside Rg1 may affect the absorption and metabolism of AC and BAC and then change their pharmacokinetic parameters. Subsequently, their absorption and metabolism were further investigated using the Caco-2 cell monolayer and rat liver microsomes in vitro. The Caco-2 cell monolayer absorption assay indicated that ginsenoside Rg1 could promote the absorption of AC and BAC, and the rat liver microsomes metabolism assay indicated that ginsenoside Rg1 accelerated the metabolism of AC and did not affect the other two alkaloids. All of the results indicated that ginsenoside Rg1 may reduce the toxicity of aconite and improve its efficacy by promoting the absorption of BAC and accelerating the metabolism of AC. These results could provide evidence for the compatibility mechanism of the traditional Chinese herbal formula Shenfu Decoction.